Project description:The organization of chromatin into self-interacting domains is universal among eukaryotic genomes, though how and why they form varies considerably. Here we report a chromosome-scale reference genome assembly of pepper (Capsicum annuum) and explore its 3D organization through integrating high-resolution Hi-C maps with epigenomic, transcriptomic, and genetic variation data. Chromatin folding domains in pepper are as prominent as TADs in mammals but exhibit unique characteristics. They tend to coincide with heterochromatic regions enriched with retrotransposons and are frequently embedded in loops, which may correlate with transcription factories. Their boundaries are hotspots for chromosome rearrangements but are otherwise depleted for genetic variation. While chromatin conformation broadly affects transcription variance, it does not predict differential gene expression between tissues. Our results suggest that pepper genome organization is explained by a model of heterochromatin-driven folding promoted by transcription factories and that such spatial architecture is under structural and functional constraints.
Project description:To facilitate the functional annotation of the pepper genome, analysis of miRNAs was performed for the sequenced data from five small RNA libraries described above, representing five different tissues. Starting with a set of 5,436 plant mature miRNA sequences available in miRBase, we annotated with high confidence 176 pepper miRNAs from 64 families, of which 30 families are computationally predicted to target TFs, suggesting important roles of these miRNA families in post-transcriptional gene regulation and transcription networks consistent with previous findings.
Project description:In this study, we used the illumina high throughput sequencing approach (Sequencing-By-Synthesis, or SBS) to develop the sequence resource of black pepper. To identify micro RNAs functioning in stress response of the black pepper plant, small RNA libraries were prepared from the leaf and root of Phytophthora capsici infected plants, leaves from drought stressed and control plants.
Project description:Upon virus infections, the transcriptomic profile of host plants markedly changes. The rapid and comprehensive transcriptional reprogramming is critical to ward off virus attack. To learn more about transcriptional reprogramming in tobamovirus-infected pepper leaves, we carried out transcriptome-wide RNA-Seq analyses of pepper leaves following Obuda pepper virus (ObPV) and Pepper mild mottle virus (PMMoV)-inoculations.
Project description:To facilitate the functional annotation of the pepper genome, analysis of miRNAs was performed for the sequenced data from five small RNA libraries described above, representing five different tissues. Starting with a set of 5,436 plant mature miRNA sequences available in miRBase, we annotated with high confidence 176 pepper miRNAs from 64 families, of which 30 families are computationally predicted to target TFs, suggesting important roles of these miRNA families in post-transcriptional gene regulation and transcription networks consistent with previous findings. To identify genomic regions generating small RNAs, we applied previously described analytical strategies to five small RNA libraries from different tissues. Developing roots, stems and mature leaves were collected from plants grown in soil in a green house at 22 °C with a 16 hr light cycle and harvested from plants at full-bloom stage. Mature plants were harvested for fully open flowers. Additional flowers were allowed to self-pollinate and fruit was harvested in the breaker stage (thirty days after pollination when the fruit was turning red). Total RNA for different tissues was isolated from the frozen root samples by using the Trizol Reagent (Invitrogen) according to manufacturer’s instructions, and libraries were constructed using the Small RNA Sample Prep Kit (Illumina, San Diego, CA) as previously described, then sequenced on an Illumina HiSeq2000 system.
